125 vs 250F

SCHAFFERNOCKER said:
What's the scoop on this? Something ive never heard before, i always make sure its in neutral.
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It was something on the yamaha 125s 05 and up. Mine did it at ram jam then again 4 months later at apple cabin. The counters haft bearing just blows apart and it's all over. I've never heard of any other bikes really doing this. Someone at the shop I went to told me to put it in gear when I get done riding it. Something to do with the load on the bearing I suppose.
 
I'm not sure but when I heard it and tried it, I never had the issue again. Something tells me it worked. Lol
 
ktrop251 said:
It was something on the yamaha 125s 05 and up. Mine did it at ram jam then again 4 months later at apple cabin. The counters haft bearing just blows apart and it's all over. I've never heard of any other bikes really doing this. Someone at the shop I went to told me to put it in gear when I get done riding it. Something to do with the load on the bearing I suppose.
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Calling BS on this one. There is no mechanical reason that would make a difference. Plus I have owned 3 - 05 and up YZ 125's since 2005 , 1 of which are still with a friend of mine and a second one I still own since 2008. Another friend has an 05 for 5 years now. All of us always leave them in neutral and none of us have ever had that issue. That issue is almost ALWAYS from running your chain too tight.
 
I thought that too. Before I rode it I checked the tension and lubed it.

Chain had 2-3 finger breadths. Chain was super tight when it locked up. First thing I noticed when I looked down. Second thing I noticed was oil puking. Brought back to the truck and When I took the countershaft sprocket off the entire countershaft sucked back into the case about an inch with a loud pop.

Checked the axle blocks and they were in the same spot as before I went out to practice. So in my case I think the bearing let go and the countershaft got pulled an inch outta the case while the ball bearing blew a hole in my case at the two o'clock position near the countershaft opening. which made the chain real tight.
 
2-3 fingers is too tight, it should be 3 good fingers at the back of the chain buffer on top of the swing arm.
 
hershey said:
Calling BS on this one. There is no mechanical reason that would make a difference. Plus I have owned 3 - 05 and up YZ 125's since 2005 , 1 of which are still with a friend of mine and a second one I still own since 2008. Another friend has an 05 for 5 years now. All of us always leave them in neutral and none of us have ever had that issue. That issue is almost ALWAYS from running your chain too tight.
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Well then, Mr. Hershey I stand corrected. However, I do keep my chain in spec. Three big fat manly fingers. Still a mystery is to why mine happened twice in a row. That was what I was told, not saying I do it every time but it hasn't happened in a few years (knock on wood.) I just know it sucked when it did happen, quite expensive replacing a case half..
 
I'm not supporting the chain tension argument, but the tension changes by a lot when you compress the suspension. If you're not sure, sit on your bike and check it then. There should still be a little bit of play.
 
Was it muddy? If your chain was in the tighter side of adjustment and you got sand or gravel up through the countershaft sprocket while compressing suspension you could break the case I would think.
 
The ball bearing brokenThe case. Broke right at the bearing protruding through.
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C Hudak said:
Maybe some issue with the oil getting to that bearing?
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This bike was recovered as stolen at one time. Coulda had the s**t wheelied out of it. Not sure though. Because the rest of the inside looks good. One shift fork is tore up. Mall gears and clutch werent affected. Lucked out.
 
GeorgiePorgie said:
I thought that too. Before I rode it I checked the tension and lubed it.

Chain had 2-3 finger breadths. Chain was super tight when it locked up. First thing I noticed when I looked down. Second thing I noticed was oil puking. Brought back to the truck and When I took the countershaft sprocket off the entire countershaft sucked back into the case about an inch with a loud pop.

Checked the axle blocks and they were in the same spot as before I went out to practice. So in my case I think the bearing let go and the countershaft got pulled an inch outta the case while the ball bearing blew a hole in my case at the two o'clock position near the countershaft opening. which made the chain real tight.
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Was that the same bike that gave you trouble when getting the sprocket off?
I rode my '06 just today. It finally has a normal feeling clutch with a new clutch basket. Those shift stopper bearing parts bouncing around in there messed a few things up.

The 125 is the way to go for your son, John250. It's even fun for big, old guys...
 
I'm not saying this proposal will be approved. But there is a proposal going into our rules making body that basically says you must be 14 to ride a 250F and 16 to ride a 450F. If the proposal is passed in October, it wouldn't go into effect until 2017. So I would hold off on buying your 12 year old a 250F until Christmas. Call your local AMA congressman and voice your opinion.
 
John250 said:
My son Matthew just turned 12 years old, and rides Mini Jr. He is a big kid. Probably 5'4 and 145 lbs. Just out growing an 85. I don't want to hassle with building a supermini.

I thought I would move him to a 125 after all the series races end in September. Today he rode a 250F for the first time on a big bike. Took some slow laps and by the time he was done was jumping everything he does on his 85 and looking more comfortable on it.

Now I am wondering......mess with a 125, a bike without a class, or just go 250F? He is a smooth rider, so I now I am thinking maybe 250F. Suggestions??
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I'm in your shoes right now. My 11 year old (5'5", 130pds.) has been on a YZ125 most of this year. He had a supermini and the 125 at the beginning of the season, but very quickly moved past the mini once he threw a leg over the big bike. He handles it great and I don't have to worry about him having too much engine or too heavy a bike. He can push it hard and throw it around. We're concentrating on cornering and overall riding technique. We'll be on it next year as well and then possibly a 250F for 2017. In short I would recommend the 125 for at least a season.
These small developmental phases our kids go through don't always last long, but they are hugely important. 3 years ago my kid was on a 65. Now, just before turning 12, he's riding practice with A/B riders, holding his own AND geting better everyday. Good stuff!
 
Alex186 said:
I'm not saying this proposal will be approved. But there is a proposal going into our rules making body that basically says you must be 14 to ride a 250F and 16 to ride a 450F. If the proposal is passed in October, it wouldn't go into effect until 2017. So I would hold off on buying your 12 year old a 250F until Christmas. Call your local AMA congressman and voice your opinion.
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Alex, I'm not sure how much say you have with the rule making, but if you would make sure they think it through. I completely understand the thought process with this particular proposal. I think there needs to be a means for a provisional of some manner to make exceptions. I haven't given that part much thought as I am out of the fight for now.
My personal experience with my own son was a little nerve racking at times. At age 9 he was 4' 11" tall and 105 pounds racing a 65 at Loretta's. By age 11 he was 5' 8", 140 pounds practicing on a 125 and 250F. At 13 (now) he is 6' 2" and 160 pounds. By all accounts he is not a novice rider, but as a dad, it scares the life out of me at times, putting him in with the more mentally and physically mature group of intermediate riders.
By no means am I saying the exception is the rule, but maybe there should be some thought put into a provisional of sort.
Back on topic... I believe the next stop after or during super's is deff. a 125.
 
Better add a weight clause to that 14 year old rule Alex. Just ask Tyler bowers and many other big kids of the past....

@k01. Was the same bike I had a problem getting the countershaft nut off. Used a torque wrench to put it back on. And it was extremely tight and difficult to take off once it let go.
 
GeorgiePorgie said:
Better add a weight clause to that 14 year old rule Alex. Just ask Tyler bowers and many other big kids of the past....

@k01. Was the same bike I had a problem getting the countershaft nut off. Used a torque wrench to put it back on. And it was extremely tight and difficult to take off once it let go.
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This topic is very interesting and relevant to us, we have always been in this situation since we've been in mx and know of others that have had this same issue. This isn't a complaint just an observation that in most sports weight is a deciding factor of what position they are going to play, what weight class they are going to be in, etc. but in motocross it seems to be irrelevant and in my opinion it shouldn't be. I was recently checking into gocart racing for my daughter who is also big for her age and it was interesting because they divided the riders into CC's, age and weight. I thought it made a lot of sense to factor in weight because there's a direct correlation between horsepower and weight (speed). So, as we know some kids are bigger than others and in motocross they have to move on to a larger bike regardless if their skill level or mental ability or muscle structure is ready for it or not. Talking with some of the parents of these larger kids we have always said there should be some sort of distinction or separation between the kids that that are older on big bikes as well as the kids that are younger or older on very small cc bikes. So, it would make sense to me to somehow factor in the fact that a kid who is very young but due to his size has to move on to bigger bikes, could still race against kids their age. And yes, I know it sounds like I'm trying to make another class, I'm not and we will deal with the way it but it's never seemed like a very fair situation for those that get pushed on and race much older kids before they are ready for it.
 
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